The primary objective of this research is to provide new information on the sensory processing capabilities and the functional significance of a mechanoreceptive lateral line system. Behavioral techniques using a stereotyped feeding behavior will be used to measure the response of the mottled sculpin lateral line to live prey and artificial stimuli in terms of (1) threshold levels and frequency range of responsiveness, (2) spatial receptive field and (3) distance and direction determination. In addition, the effects of background levels of water motion on these capabilities will be examined. Physiological techniques will be used to determine how stimulus features are coded in peripheral neurons to reveal the contribution of the peripheral nervous system to processing by the entire system, as measured behaviorally.